tests: Use properties to change values
tests: Use properties to change values

The values inside _init() should match the default values of the
properties as specified by the GParamSpec. If we want to verify
a non-default value we should specify the value when instantiating
the object.

GNOME/json-glib,oerdnj/json-glib,ebassi/json-glib,Distrotech/json-glib,ebassi/json-glib,Distrotech/json-glib,Distrotech/json-glib,brauliobo/json-glib,robtaylor/json-glib-gvariant,brauliobo/json-glib,oerdnj/json-glib,GNOME/json-glib,frida/json-glib,brauliobo/json-glib,robtaylor/json-glib-gvariant,oerdnj/json-glib,oerdnj/json-glib,frida/json-glib,ebassi/json-glib